
#include <sys/cdefs.h>
#if !defined(_KERNEL) && !defined(_STANDALONE)
#include <assert.h>
#include <inttypes.h>
#include <limits.h>
#include <string.h>
#else
#include <lib/libkern/libkern.h>
#endif

#define FAST_STRPBRK 1
#define UC(a) ((unsigned int)(unsigned char)(a))

#ifdef FAST_STRPBRK
#define ADD_NEW_TO_SET(i) (set[inv[i] = idx++] = (i))
#define IS_IN_SET(i) (inv[i] < idx && set[inv[i]] == (i))
#define ADD_TO_SET(i) (void)(IS_IN_SET(i) || /*LINTED no effect*/ADD_NEW_TO_SET(i))
#else
#define IS_IN_SET(i) (set[(i) >> 3] & idx[(i) & 7])
#define ADD_TO_SET(i) (void)(set[(i) >> 3] |= idx[(i) & 7])
#endif

char *
strpbrk(const char *s, const char *charset)
{
#ifdef FAST_STRPBRK
	uint8_t set[256], inv[256], idx = 0;
#else
	static const size_t idx[8] = { 1, 2, 4, 8, 16, 32, 64, 128 };
	uint8_t set[32];

	(void)memset(set, 0, sizeof(set));
#endif

	_DIAGASSERT(s != NULL);
	_DIAGASSERT(charset != NULL);

	if (charset[0] == '\0')
		return NULL;
	if (charset[1] == '\0')
		return strchr(s, charset[0]);

	for (; *charset != '\0'; ++charset)
		ADD_TO_SET(UC(*charset));

	for (; *s != '\0'; ++s)
		if (IS_IN_SET(UC(*s)))
			return __UNCONST(s);
	return NULL;
}
